Control Module

The control module is an integral part of the ABS unit and has a 26-pin connector.
A wheel sensor at each wheel sends a wheel-speed signal to the control module.
The ABS functions such that if the speed of a wheel is retarded more than that of the other wheels, the solenoid valves and return pump modulate the hydraulic brake pressure. The pressure can either be held constant or be reduced to enable the maximum braking effect to be achieved by each individual wheel on the prevailing road surface.
The EBID function incorporated in the control module controls the distribution of the brake force between the front and rear wheels by means of solenoid valves.
The control module receives a continuous power supply from the +30 circuit and is designed for a working voltage of between 9 "Ad 16 V.
Turning the ignition switch to ON activates the control module. The control module causes the ABS lamp to come on as a function test. It goes out after 3-5 seconds if no faults are detected.
Always ground yourself, e.g. on the engine block, before touching the control module and avoid touching the terminal pins.
The control module incorporates the following components:
^ Main relay
^ Pump relay


Main relay
The integral main relay supplies power to the solenoid valves and pump relay and cannot be replaced separately.


Pump relay
The integral pump relay supplies power to the return pump and cannot be replaced separately.


Diagnosis
The control module monitors its own internal functions and the other ABS-system components.
In the event of an internal control module fault, diagnostic trouble code C1605 will be generated and the ABS system disconnected at the same time as the ABS lamp, the brake fluid warning lamp and the central warning lamp come on.